The present invention relates to a wafer transferring robot for transferring wafers such as semiconductor wafers.
Priorly, a wafer transferring robot is, for example, as shown in FIG. 13, provided with a rotating base 20 supported so as to be rotatable on a base 10, and two robot arms 30A and 30B are arranged laterally symmetrically on the rotating base 20. Robot arms 30A and 301 are provided with first arms 320A and 320B supported so that one end of each is driven to rotate by the driving motors 310A and 310B; on the other ends of the first arms 320A and 320B, one end of each of the second arms 330A and 330B are supported so as to be driven to rotate; on the other ends of the second arms 330A and 330B, one end of each of the third arms 340A and 340B are supported so as to be driven to rotate; and on the other ends of the third arms 340A and 340B, chucks 40A and 40B for holding a wafer W are provided, respectively.
Herein, when the first arms 320A and 320B, second arms 330A and 330B, and third arms 340A and 340B rotate and chucks 40A and 40B are distant from the rotating base 20 by a predetermined distance, in order to prevent interference between chucks 40A and 40B, a robot is disclosed (for example, in Japanese Laid-open Patent Publication No. 274140 of 1996) wherein one of the third arms 340A and 340B is formed in a U-shaped and whereby the chucks 40A and 40B are separated in the vertical direction.
In the abovementioned prior art, since the first arms 320A and 320B and second arms 330A and 330B are mounted with the third arms 340A and 340B and chucks 40A and 40B, enhanced rigidity is necessary. However, since the third arms 340A and 340B do not necessitate great rigidity, and in order to improve operation properties by reducing inertia, it is necessary to configure them so as to have relatively smaller rigidity.
Also, there is another problem in that, when the third arms 340A and 340B have improved rigidity, since form dimensions enlarge and weight increases, the capacity of the arm driving motors has to be increased.
The object of the present invention is to provide a wafer transferring robot capable of restraining the vibration; of wafers during the transfer without increasing rigidity of third arms.
According to the present invention, a wafer transferring robot comprises a rotating base arranged so as to rotate l.on a base, two horizontally extensible robot arms arranged laterally symmetrically to each other on the rotating base and comprising first arms, second arms, and third arms respectively, and chucks fixed to the third arms, respectively; wherein the linear movable devices consist of linear motors, wherein mobile elements fixed, so as to be vertically erect, to transferring parts arranged so as to be vertically erect and stators fixed, so as to be perpendicularly erect, on the rotating base are arranged so as to be horizontally opposed, and besides, in one robot arm, the third arm is over the second arm, and the third arm of the other robot arm is below the second arm so as to be opposed to the third arm of said former robot arm.
Furthermore, the wafer transferring robot comprising a rotating base arranged so as to rotate on a fixed base, linear movable devices horizontally extended on the rotating base, holding parts fixed to transferring parts of the linear movable devices, and chucks fixed to the holding parts; wherein the linear movable devices consist of linear motors, wherein mobile elements fixed, so as to be vertically erect, to transferring parts arranged so as to be vertically erect and stator fixed, so as to be perpendicularly erect, on the rotating base are arranged so as to be horizontally opposed, and besides, the plurality of linear motors horizontally arranged in parallel to each other, and the holding parts are arranged at places where wafers held by the chucks do not interfere with each other, respectively.
Furthermore, the linear movable devices comprise linear motors for driving the transferring parts.
Furthermore, the linear movable devices comprise belt movable devices for driving the transferring parts.
Furthermore, the linear movable devices comprise cylinders for driving the transferring parts.
Furthermore, the linear movable devices are horizontally arranged side by side on the rotating base.
Furthermore, the linear movable devices are vertically arranged to be stacked up on the rotating base.
Accordingly, without increasing rigidity of the third arms the rigidity of the transferring parts can be so enhanced that: the vibration of wafers WA and WB can be prevented.
As described above, the following effects are provided according to the present invention,
(1) Since the chucks are supported by the linear movable devices having configurations with high rigidity, the vibration of wafers during transfer can be prevented,
(2) Since the linear movable devices consist of linear motors wherein movable elements and stators are arranged to be horizontally opposed, and the plurality of linear motors are horizontally arranged in parallel to each other, a great number of wafers can be transferred at the same time and a high quality wafer transferring robot, which can deal with and a plurality of compact processing operations and restrain vibration, can be provided.